Waterproof housings for electronic devices are known in the art. However waterproofing solutions that function well with smaller devices (e.g., mobile phones) may tend to function less well when scaled up and applied to larger devices (e.g., tablet computers). For example, the use of a radially compressed gasket works well with polycarbonate cases for phones. But, when applied to larger cases, radial compression may tend to cause the structure to flex and decrease the performance of the gasket seal. There is, therefore, a need for waterproof cases for larger devices that are lightweight and maintain an air and watertight seal. Improvements are also needed in the sound transmission for such cases.